Dhiraj,
Chart dimensions may also be calculated from an expression.
You try understanding the basics of chart dimensions and expressions below.
When you create a chart, you should first ask yourself two questions:
What do you want to look at? What should the sizes of the bars in the bar chart correspond to? The answer might be the "sum of sales", or something similar. This is set on the Expressions tab.
What do you want to group it by? Which field values do you want to use as labels for the bars in the bar chart? The answer might be "per country", or something similar. This is set on the Dimensions tab.
A chart can display one or more dimensions. The upper limit depends on the actual chart type, the complexity of the data and the available memory. Pie, line and scatter charts can display a maximum of two dimensions, bar, block and grid charts three. Radar charts can only display a single dimension, and gauge charts use no dimensions at all. A funnel chart typically has one to three dimensions. Further dimensions are ignored.
A chart dimension gets its values from a field which is specified on the Chart Properties: Dimensions page. Instead of being a single field a dimension can also consist of a group of fields (see Edit Groups below).
A dimension can be a single field, a group or an expression (calculated dimension).
Hope it helps.
Regards.
Siva
